Record whether it is concentrated near the door or an internal opening. Its position can help describe moisture entry or airflow conditions without identifying a failed part remotely.
What the observation tells you
A top package may also project into an area that should remain clear. Do not scrape overhead ice while food is beneath it or remove a fixed ceiling panel. Falling fragments can damage packaging and conceal the original pattern.
A useful next step
Take a safe photograph, check ordinary loading clearances and follow the model's owner-care advice. Recurrent thick frost or unreliable temperatures needs assessment.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.